JP2014028027A - Ultrasonic diagnostic apparatus, switching control program and switching control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a dual three level pulser circuit, secure the same performance as that of a five level pulser circuit and improve image quality performance of an ultrasonic image.SOLUTION: A transmission section of an ultrasonic diagnostic apparatus includes: a rate pulse generation section for generating a rate pulse; a transmission delay section for giving the rate pulse delay time for each vibrator; a pulser 49 that generates a voltage signal for driving respective vibrators in synchronization with the rate pulse delayed; and a pulser control section 45 for controlling the pulser 49. The pulser 49 includes: a high voltage generation section 71 for generating a first high voltage indicating a potential difference between a first potential and an earth potential and a second high voltage indicating a potential difference between a second potential having an absolute value higher than that of the first potential and the earth potential; and a plurality of switching elements capable of mutually switching a potential among the first potential, the second potential and the earth potential. The pulser control section 45 controls the plurality of switching elements so as to switch the potential from the second potential to the first potential via the earth potential.

Description

  Embodiments described herein relate generally to an ultrasonic diagnostic apparatus having a dual 3-level pulser, a switching control program and a switching control method for controlling the dual 3-level pulser.

  The ultrasonic diagnostic apparatus has a pulsar circuit for generating an ultrasonic wave by driving a transducer of an ultrasonic probe. Usually, a three-level pulser circuit having three voltage levels is used for the pulser circuit. In addition, a dual pulser circuit is used when time-division scanning is performed in two modes (B mode and Doppler mode). Two types of high voltages applied from two types of ultrasonic transmission power sources are applied to the dual pulser circuit.

  Further, as the pulsar circuit, a five-level pulsar circuit having five kinds of voltage levels may be used. By controlling the transmission amplitude for each channel using a five-level pulsar circuit, pseudo Gaussian transmission, transmission apodization, two-way simultaneous transmission in which two transmission sound fields are superimposed (2TxBeams), and Bifocal simultaneous transmission is being implemented.

  For example, the following three methods are known for realizing a five-level pulser circuit for realizing pseudo-Gaussian transmission, transmission apodization, two-way simultaneous transmission, two-focus simultaneous transmission, and the like. The first method uses a five-level dedicated circuit or a linear driver (high voltage DAC) (hereinafter referred to as a five-level pulser). At this time, the number of transmission control signals input to the 5-level pulser is three. The output from the 5-level pulser is 5 levels of 4 types of positive and negative high voltages (± 2, ± 1) and zero voltage.

  The second and third methods are methods using a dual three-level pulser circuit, for example, as shown in FIG. The second method is a method of providing a high voltage signal adding circuit at the output of the dual three-level pulser circuit. In the third method, the number of transmission control signals input to the dual three-level pulser circuit is four.

  However, the first to third methods have the following problems. In the first and second methods, the scale of the pulsar circuit is increased. For this reason, an increase in cost becomes a problem in mounting on an ultrasonic diagnostic apparatus as a multi-channel transmission circuit. In the third method, there is a problem that the transient response time is long in the change of the drive voltage applied to the vibrator. Specifically, for example, in two kinds of voltages V2 and V1 (V2> V1), as shown in FIG. 8, at the time of voltage fall (+ V2 → + V1) and rise (−V2 → −V1), as shown in FIG. The effect of response time appears in the drive voltage waveform. In order to solve this problem, a dedicated circuit (for example, Active HV Clamper) or the like is required, which causes a problem that the circuit scale increases and the cost increases.

JP 2008-252436 A

  The purpose is to use a dual 3-level pulsar circuit to ensure performance equivalent to that of a 5-level pulsar circuit and to improve the image quality of ultrasonic images, and a switching control program for controlling the dual 3-level pulsar. And providing a switching control method.

  The ultrasonic diagnostic apparatus according to the present embodiment includes an ultrasonic probe having a plurality of transducers, a transmission unit that transmits ultrasonic waves to the subject via the transducer, and the subject from the subject via the transducer. A reception unit that receives an ultrasonic echo; and an image generation unit that generates image data based on an output of the reception unit, wherein the transmission unit generates a rate pulse that determines a transmission period of the ultrasonic wave. A rate pulse generator, a transmission delay unit for giving a delay time to the rate pulse for each transducer, and a pulser for generating a voltage signal for driving each transducer in synchronization with the delayed rate pulse. And a pulser controller that controls the pulser to generate the voltage signal, the pulser having a first high voltage indicating a potential difference between a first potential and a ground potential and an absolute value of the first pulse voltage. Higher than potential A high voltage generator that generates a second high voltage indicating a potential difference between two potentials and the ground potential, and a plurality of potentials that can be switched between the first potential, the second potential, and the ground potential. The pulsar control unit controls the plurality of switching elements in order to switch the potential from the second potential to the first potential via the ground potential.

FIG. 1 is a configuration diagram showing the configuration of the ultrasonic diagnostic apparatus according to the present embodiment. FIG. 2 is a configuration diagram illustrating an example of a configuration of a transmission unit according to the present embodiment. FIG. 3 is a configuration diagram illustrating an example of a configuration of the pulsar control unit according to the present embodiment. FIG. 4 is a configuration diagram illustrating an example of the configuration of the pulser according to the present embodiment. FIG. 5 is a diagram illustrating a plurality of switching pulses output from the pulsar control unit to the pulsar, together with voltage signals output from the pulsar, according to the present embodiment. FIG. 6 is a diagram illustrating an example of a flowchart illustrating a procedure for generating a voltage signal according to the present embodiment. FIG. 7 is a diagram showing a circuit configuration of a conventional dual 3-level pulser. FIG. 8 is a diagram showing a timing chart of switching pulses together with a transition response time at the rise and fall of the drive voltage in the conventional dual three-level pulser.

  The ultrasonic diagnostic apparatus according to this embodiment will be described below with reference to the drawings. In the following description, components having substantially the same configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.

  FIG. 1 is a diagram illustrating a configuration of an ultrasonic diagnostic apparatus 1 according to the present embodiment. As shown in FIG. 1, the ultrasonic diagnostic apparatus 1 includes an ultrasonic probe 10, an apparatus main body 11, a monitor 13, and an input device 15.

  The ultrasonic probe 10 has a plurality of vibrators as acoustic / electric reversible conversion elements such as piezoelectric ceramics. A plurality of transducers are arranged in parallel and are provided at the tip of the ultrasonic probe 11.

  Hereinafter, in order to simplify the description, it is assumed that one vibrator constitutes one channel. The plurality of transducers generate ultrasonic waves in response to voltage signals respectively supplied from a plurality of pulsers of the transmission unit 21 described later. Each of the plurality of transducers generates an echo signal in response to reception of the ultrasonic echo reflected from the living tissue of the subject. The ultrasonic probe 11 may be a one-dimensional array probe in which a plurality of transducers are arranged in one dimension, or a two-dimensional array probe in which a plurality of transducers are arranged in two dimensions. Also good.

  The apparatus body 11 includes a transmission unit 21, a reception unit 23, a B-mode processing unit 25, a Doppler processing unit 27, an image generation unit 29, an image composition unit 31, an internal storage device 33, an interface unit 35, and a control processor (Central Processing Unit: (Hereinafter referred to as CPU) 37.

  Although not shown in FIG. 1, the transmission unit 21 includes a rate pulse generation unit, a transmission delay unit, a pulsar control unit, and a pulsar. FIG. 2 is a diagram showing a rate puls generation unit 41, a transmission delay unit 43, a pulsar control unit 45, and a pulsar 49 connected to one transducer 47 together with the CPU 37 in the transmission unit 21.

  The rate pulse generator 41 repeatedly generates a rate pulse for forming a transmission ultrasonic wave at a predetermined rate frequency frHz (cycle: 1 / fr sec). The generated rate pulse is distributed to the number of channels and sent to the transmission delay unit 43.

  The transmission delay unit 43 converges the transmission ultrasonic wave into a beam shape for each of a plurality of channels and determines a delay time necessary for determining transmission directivity (hereinafter referred to as transmission delay time) for each rate pulse. give. The transmission direction or transmission delay time of transmission ultrasonic waves (hereinafter referred to as a transmission delay pattern) is stored in the internal storage device 33 described later. The transmission delay pattern stored in the internal storage device 33 is referred to at the time of ultrasonic transmission by the CPU 37, which will be described later, according to ultrasonic transmission waveform data (hereinafter referred to as transmission waveform).

  The pulsar control unit 45 generates a switching pulse for controlling each of a plurality of switching elements in the pulsar 49 described later, based on the rate pulse given the transmission delay time and the transmission waveform read from the CPU 37. . The pulsar control unit 45 outputs the generated plurality of switching pulses to the plurality of switching elements. Hereinafter, for the sake of specific explanation, a case where two-way simultaneous transmission of ultrasonic waves is applied to the present embodiment will be described. Note that bifocal simultaneous transmission, pseudo-Gaussian transmission, and transmission apodization may be applied to this embodiment.

  FIG. 3 is a configuration diagram illustrating an example of the configuration of the pulsar control unit 45. The pulsar control unit 45 includes a plurality of memories (hereinafter referred to as a first memory 51 and a second memory 53), and a first delay unit 55 and a second delay unit connected to the first memory 51 and the second memory 53, respectively. 57, an adder 59, and a switching pulse generator 61.

  Each of the first and second memories stores a plurality of transmission waveforms respectively corresponding to two directions in the two-way simultaneous transmission. For example, the first memory 51 stores a transmission waveform corresponding to the first direction (hereinafter referred to as a first transmission waveform). The second memory 53 stores a transmission waveform (hereinafter referred to as a second transmission waveform) corresponding to the second direction. The plurality of stored transmission waveforms are output from the CPU 37 described later.

  The first delay unit 55 delays the first transmission waveform based on the rate pulse to which the transmission delay is given by the transmission delay unit 43. The second delay unit 57 delays the second transmission waveform based on the rate pulse to which the transmission delay is given by the transmission delay unit 43. The delayed first and second transmission waveforms are output to an adder 59 described later.

  The adder 59 adds the delayed first and second transmission waveforms to generate an added transmission waveform (hereinafter referred to as an addition transmission waveform). Adder 59 outputs the added transmission waveform to switching pulse generator 61.

  The switching pulse generator 61 generates a plurality of switching pulses to be output to a pulser 49 described later based on the added transmission waveform. The switching pulse generator 61 outputs the generated switching pulses to a plurality of switching elements in the switching unit of the pulser 49 described later.

  Specifically, the switching pulse generator 61 identifies a time point (hereinafter referred to as a first time point) for switching from the positive second high voltage to the positive first high voltage based on the added transmission waveform. The switching pulse generator 61 specifies a time point (hereinafter referred to as a second time point) for switching from the negative second high voltage to the negative first high voltage based on the added transmission waveform. The positive / negative first high voltage and the positive / negative second high voltage will be described later. Note that the first time point and the second time point in the added transmission waveform may be specified by determination based on two predetermined threshold values respectively corresponding to the first time point and the second time point.

  The first high voltage represents a potential difference between the ground potential and the first potential. The first high voltage (± V1) has two types of positive and negative polarities. The absolute value (| + V1 |) of the positive first high voltage is equal to the absolute value (| −V1 |) of the negative first high voltage (| + V1 | = | −V1 |). The second high voltage represents a potential difference between the ground potential and the first potential. The second high voltage (± V2) has two types of positive and negative polarities. The absolute value (| + V2 |) of the positive second high voltage is equal to the absolute value (| −V2 |) of the negative second high voltage (| + V2 | = | −V2 |).

  In addition, the absolute value of the second potential is greater than the absolute value of the first potential. That is, the absolute value of the second high voltage (± V2) is larger than the absolute value of the first high voltage (± V1) (| ± V2 |> | ± V1 |). The positive and negative first high voltage is generated by a first high voltage generator in a high voltage generator described later. The positive and negative second high voltage is generated by a second high voltage generation unit of a high voltage generation unit described later.

  The switching pulse generator 61 reads a first predetermined time stored in the internal storage device 33 described later from the internal storage device 33. The switching pulse generator 61 is a switching pulse for turning on a switching element connected to the first ground (hereinafter referred to as a first ground switch) for a first predetermined time from the specified first time point. (Hereinafter referred to as a first ground switching pulse). The switching pulse generator 61 outputs a first ground switching pulse (hereinafter referred to as G1EN) to a first ground switch (hereinafter referred to as GSW1).

  The switching pulse generator 61 reads a second predetermined time stored in the internal storage device 33 described later from the internal storage device 33. The switching pulse generator 61 is a switching pulse for turning on a switching element connected to the second ground (hereinafter referred to as a second ground switch) for a second predetermined time from the specified second time point. (Hereinafter referred to as a second ground switching pulse). The switching pulse generator 61 outputs a second ground switching pulse (hereinafter referred to as G2EN) to a second ground switch (hereinafter referred to as GSW2). Note that the first predetermined time and the second predetermined time may be the same time interval.

  In the above description, the number of switching elements belonging to the ground is two, but may be one. The switching pulse generator 61 generates a switching pulse for turning on the switching element connected to the ground for the first and second predetermined times from the specified first and second time points, respectively. The switching pulse generator 61 outputs the generated switching pulse to a switching element connected to the ground.

  The switching pulse generator 61 specifies the time (hereinafter referred to as the first positive voltage application time) for applying the positive first high voltage to the vibrator based on the added transmission waveform. The switching pulse generator 61 turns on a switching element (hereinafter referred to as a first positive switch) connected to the positive output of the first high voltage generator over the specified first positive voltage application time. Switching pulses (hereinafter referred to as first positive switching pulses) are generated. The switching pulse generator 61 outputs a first positive side switching pulse (hereinafter referred to as HVP1EN) to a first positive side switch (hereinafter referred to as PSW1).

  The switching pulse generation unit 61 specifies a time for applying a negative first high voltage to the vibrator (hereinafter referred to as a first negative voltage application time) based on the added transmission waveform. The switching pulse generator 61 turns on a switching element (hereinafter referred to as a first negative switch) connected to the negative output of the first high voltage generator over the specified first negative voltage application time. Switching pulses (hereinafter referred to as first negative switching pulses) are generated. The switching pulse generator 61 outputs a first negative side switching pulse (hereinafter referred to as HVN1EN) to a first negative side switch (hereinafter referred to as NSW1).

  The switching pulse generation unit 61 specifies a time for applying the positive second high voltage to the vibrator (hereinafter referred to as a second positive voltage application time) based on the added transmission waveform. The switching pulse generator 61 turns on a switching element (hereinafter referred to as a second positive switch) connected to the positive output of the second high voltage generator over the specified second positive voltage application time. Switching pulses (hereinafter referred to as second positive-side switching pulses) are generated. The switching pulse generator 61 outputs a second positive side switching pulse (hereinafter referred to as HVP2EN) to a second positive side switch (hereinafter referred to as PSW2).

  The switching pulse generation unit 61 specifies a time during which the negative second high voltage is applied to the vibrator (hereinafter referred to as a second negative voltage application time) based on the added transmission waveform. The switching pulse generator 61 turns on a switching element (hereinafter referred to as a second negative switch) connected to the negative output of the second high voltage generator over the specified second negative voltage application time. Switching pulses (hereinafter referred to as second negative-side switching pulses) are generated. The switching pulse generator 61 outputs a second negative side switching pulse (hereinafter referred to as HVN2EN) to a second negative side switch (hereinafter referred to as NSW2).

  The pulsar 49 generates a voltage signal for driving the vibrator 47 by switching control based on an output from the pulsar control unit 45. The waveform of the voltage signal corresponds to the added transmission waveform. Thereby, an ultrasonic beam is transmitted to the subject. The pulser 49 has a function as a dual pulser whose output voltage is three levels. FIG. 4 is a diagram illustrating an example of the configuration of the pulsar 49. The pulser 49 includes a high voltage generation unit 71 and a switching unit 73.

  The high voltage generation unit 71 includes a first high voltage generation unit 711 and a second high voltage generation unit 713. The positive output of the first high voltage generator 711 is connected to PSW1. The negative output of the first high voltage generator 711 is connected to NSW1. The positive output of the second high voltage generator 713 is connected to PSW2. The negative output of the second high voltage generator 713 is connected to NSW2. GSW1 and GSW2 are connected to the ground.

  The switching unit 73 includes a plurality of switching elements (PSW1, PSW2, NSW1, NSW2, GSW1, and GSW2). A switching pulse generated by the pulser controller 45 is input to each of the plurality of switching elements. Specifically, the switching of PSW1 is controlled by the input of HVP1EN. The switching of PSW2 is controlled by the input of HVP2EN. The switching of NSW1 is controlled by the input of HVN1EN. The switching of NSW2 is controlled by the input of HVN2EN. The switching of GSW1 is controlled by the input of G1EN. The switching of GSW2 is controlled by the input of G2EN.

  FIG. 5 is a diagram showing a plurality of switching pulses generated by the switching pulse generator 61 of the pulser controller 45 together with voltage signals output from the pulser 49. In order to simplify the explanation, the addition transmission waveform corresponding to the voltage signal in FIG. 5 is a sine wave.

  In order to apply the positive first high voltage P1 to the vibrator at time t1 for the first positive voltage application time tp1, HVP1EN is output to PSW1. In order to apply the positive second high voltage P2 to the vibrator at time t2 for the second positive voltage application time tp2, HVP2EN is output to PSW2. At time t3, G1EN is output to GSW1 in order to set the potential to the vibrator to the ground potential for the first predetermined time tg1. In order to apply the positive first high voltage P1 to the vibrator at time t4 for the first positive voltage application time tp1, HVP1EN is output to PSW1.

  In order to apply the negative first high voltage N1 to the vibrator at time t5 for the first negative voltage application time tn1, HVN1EN is output to NSW1. In order to apply the negative second high voltage N2 to the vibrator at time t6 for the second negative voltage application time tn2, HVN2EN is output to NSW2. At time t7, G2EN is output to GSW2 in order to set the potential of the vibrator to the ground potential for the second predetermined time tg2. In order to apply the negative first high voltage N1 to the vibrator at time t8 for the first negative voltage application time tn1, HVN1EN is output to NSW1.

  The first predetermined time tg1 and the second predetermined time tg2 are based on the first positive voltage application time tp1, the first negative voltage application time tn1, the second positive voltage application time tp2, and the second negative voltage application time tn2. A short time interval may be used.

  The receiving unit 23 includes a preamplifier, an analog / digital converter, a reception delay circuit, and an adder (not shown). The preamplifier amplifies the echo signal from the subject captured via the ultrasonic probe 10 for each channel. The analog-digital converter converts the amplified echo signal from an analog signal to a digital signal. The reception delay circuit gives a delay time necessary for determining the reception directivity to the echo signal converted into the digital signal. The adder adds a plurality of echo signals converted into digital signals according to the reception delay pattern. By this addition, the reflection component from the direction corresponding to the reception directivity is emphasized. The transmission directivity and the reception directivity determine the overall directivity of ultrasonic transmission / reception (the so-called “ultrasonic scanning line” is determined by this directivity).

  The receiving unit 23 may have a parallel reception function for simultaneously receiving echo signals generated on a plurality of scanning lines by one ultrasonic transmission.

  The B mode processing unit 25 includes an envelope detector and a logarithmic converter (not shown). The envelope detector performs envelope detection on the input signal to the B-mode processing unit 25, that is, the digital signal output from the receiving unit 23. The logarithmic converter relatively emphasizes weak signals by logarithmically converting the amplitude of the detection signal. Through these processes, the B-mode processing unit 25 generates B-mode data. The B mode processing unit 25 outputs the generated B mode data to an image generation unit 29 described later.

The Doppler processing unit 27 includes a Doppler signal generation unit and a color Doppler data generation unit that are not shown. The Doppler signal generator has a mixer and a low-pass filter (hereinafter LPF) not shown. The mixer multiplies the signal output from the receiving unit 23 by a reference signal having the same frequency f ₀ as the transmission frequency. By this multiplication, a signal having a component of Doppler shift frequency f _d and a signal having a frequency component of (2f ₀ + f _d ) are obtained. The LPF removes a signal having a high frequency component (2f ₀ + f _d ) from signals having two types of frequency components from the mixer. Doppler signal generating unit, by removing the signal of the high frequency component (2f 0 + _{f d),} to generate a Doppler signal having a component of the Doppler shift frequency f _d. Note that a quadrature detection method may be employed as the Doppler signal generation unit.

  The color Doppler data generation unit has an analog-digital (hereinafter referred to as A / D) converter (not shown) composed of two channels and a speed / dispersion / Power calculation unit. The A / D converter converts the Doppler signal output from the LPF of the Doppler signal generation unit or the analog signal subjected to quadrature detection into a digital signal. The velocity / dispersion / Power calculator includes an MTI (Moving Target Indicator) filter and an autocorrelation calculator (not shown).

  The MTI filter removes Doppler components (clutter components) caused by respiratory movement or pulsatile movement of the organ from the Doppler signal output from the A / D converter. The autocorrelation calculator calculates an autocorrelation value for the Doppler signal from which only blood flow information is extracted by the MTI filter. The autocorrelation calculator calculates an average velocity value and a variance value of the blood flow based on the calculated autocorrelation value. The color Doppler data generation unit generates color Doppler data from an average velocity value and a variance value of blood flow based on a plurality of Doppler signals. Hereinafter, the Doppler signal generated by the Doppler signal generator and the color Doppler data generated by the color Doppler data generator are collectively referred to as Doppler data. The Doppler processing unit 27 outputs the generated Doppler data to the image generation unit 29.

  The image generator 29 has a digital scan converter (Digital Scan Converter: hereinafter referred to as DSC) not shown. The image generating unit 29 performs coordinate conversion processing (resampling) on the DSC. The coordinate conversion processing is, for example, conversion of a scanning line signal sequence of ultrasonic scanning composed of raw data into a scanning line signal sequence of a general video format represented by a television or the like. Here, the raw data is Doppler data or B-mode data. The image generation unit 29 performs an interpolation process on the DSC following the coordinate conversion process. Interpolation processing is processing for interpolating data between scan line signal sequences using raw data in adjacent scan line signal sequences.

  The image generating unit 29 generates an ultrasonic image as a display image by executing coordinate conversion processing and interpolation processing on the raw data. The image generation unit 29 may include an image memory that stores data (hereinafter referred to as image data) corresponding to the generated ultrasonic image. The image generation unit 29 outputs the image data to an image composition unit 31 described later. Hereinafter, an ultrasonic image generated using B-mode data is referred to as a B-mode image. An ultrasonic image generated using Doppler data is called a Doppler image. In the following description, the B-mode image and the Doppler image are collectively referred to as a tomographic image.

  The image synthesizing unit 31 synthesizes character information and scales of various parameters with the ultrasonic image. The image synthesis unit 31 outputs the synthesized ultrasonic image to the monitor 13. The image compositing unit 31 may generate an image stored in a cine memory (not shown). At this time, the image stored in the cine memory is displayed as a cine (loop reproduction).

  The internal storage device 33 includes a plurality of reception delay patterns and a plurality of transmission delay patterns having different focus depths, transmission conditions (two-direction simultaneous transmission, two-focus simultaneous transmission, pseudo-Gaussian transmission, transmission apodization, and two-part Doppler mode. Sampled gate setting, etc.), control program of the ultrasonic diagnostic apparatus 1, various data groups such as diagnostic protocols, raw data generated by the B-mode processing unit 25 and Doppler processing unit 27, generated by the image generation unit 29 The recorded ultrasonic image and the like are stored.

  The internal storage device 33 stores a plurality of transmission waveform data respectively corresponding to a plurality of transmission conditions. The internal storage device 33 stores first and second predetermined times. When specifying the first and second time points by the threshold determination, the internal storage device 33 stores two predetermined threshold values respectively corresponding to the first time point and the second time point. The internal storage device 33 may store a plurality of switching patterns (a plurality of switching pulses) respectively corresponding to a plurality of switching elements for each of a plurality of transmission conditions. The internal storage device 33 may store a switching control program for generating a plurality of switching pulses related to the added transmission waveform.

  The interface unit 35 is an interface related to the input device 15, a network, an external storage device (not shown), and a biological signal measurement unit. Data such as an ultrasound image and analysis results obtained by the apparatus main body 11 can be transferred to another apparatus via the interface unit 35 and the network. The interface unit 35 can also download a medical image related to the subject acquired by another medical image diagnostic apparatus (not shown) via a network.

  The CPU 37 selects the B mode and the Doppler mode input by the operator via the input device 15, the frame rate, the scanned depth, the two-way simultaneous transmission, the two-focus simultaneous transmission, the pseudo Gaussian transmission, and the transmission apodization. The transmission delay pattern, the reception delay pattern, and the device control program stored in the internal storage device 33 are read based on the setting of the sampling gate in the two-part Doppler mode, and the device main body 11 is controlled according to these.

  For example, the CPU 37 reads out the first and second transmission waveforms from the internal storage device 33 based on the transmission condition input via the input device 15. The CPU 37 stores the read first and second transmission waveforms in the first and second memories. Next, the CPU 37 reads out transmission delay patterns respectively corresponding to the first and second transmission waveforms from the internal storage device 33. The CPU 37 outputs the read transmission delay pattern to the transmission delay unit 43.

  The CPU 37 can also control the pulsar control unit 45 according to the switching control program stored in the internal storage device 33. Specifically, transmission conditions such as two-way simultaneous transmission, two-focus simultaneous transmission, pseudo-Gaussian transmission, transmission apodization, and setting of a sampling gate in the two-part Doppler mode are input via the input device 15. Then, the CPU 37 reads the switching control program corresponding to the input transmission condition from the internal storage device 33. The CPU 37 develops and executes the read switching control program on a memory (not shown).

  The monitor 13 displays an ultrasound image such as a B-mode image and a Doppler image based on the output of the image synthesis unit 31. Note that the monitor 13 may perform adjustments such as brightness, contrast, dynamic range, and γ correction on the displayed image.

  The input device 15 is connected to the interface unit 35 and takes various instructions, commands, information, selections, and settings from the operator into the device main body 11. The input device 15 has input devices such as a trackball, a switch button, a mouse, and a keyboard (not shown). The input device detects the coordinates of the cursor displayed on the display screen, and outputs the detected coordinates to the CPU 37 described later.

  The input device may be a touch command screen provided to cover the display screen. In this case, the input device 15 detects coordinates instructed by a touch reading principle such as an electromagnetic induction type, an electromagnetic distortion type, and a pressure sensitive type, and outputs the detected coordinates to the CPU 37. Further, when the operator operates the end button or the freeze button of the input device 15, the transmission / reception of the ultrasonic waves is ended, and the apparatus main body 11 is in a pause state.

(Voltage signal generation function)
The voltage signal generation function is a function that generates a plurality of switching pulses based on the added transmission waveform and generates a voltage signal with a reduced transient response time. Hereinafter, processing relating to the voltage signal generation function (hereinafter referred to as voltage signal generation processing) will be described.

  FIG. 6 is a diagram illustrating an example of a flowchart illustrating a procedure for generating a voltage signal. The following voltage signal generation processing is a description corresponding to two-way simultaneous transmission or two-focus simultaneous transmission, but can also be applied to pseudo-Gaussian transmission and transmission apodization.

  An ultrasonic transmission condition is input via the input device 15. Based on the input transmission condition, the first and second transmission waveforms are read from the internal storage device 33. A transmission delay pattern is read from the internal storage device 33 in accordance with the first and second transmission waveforms. In accordance with the read transmission delay pattern, a transmission delay is added to the first and second transmission waveforms based on the transmission delay rate pulse to which a transmission delay is added to the rate pulse (step Sa1).

  An added transmission waveform is generated by adding the first and second transmission waveforms to which the transmission delay is added (step Sa2). Based on the added transmission waveform, the first and second time points are identified (step Sa3). Based on the transmission addition waveform, the first and second positive application times and the first and second negative application times are specified. First and second predetermined times are read from the internal storage device 33. G1EN is generated based on the first time point and the first predetermined time, and G2EN is generated based on the second time point and the second predetermined time (step Sa4).

  HVP1EN is generated based on the added transmission waveform and the first positive voltage application time, and HVP2EN is generated based on the added transmission waveform and the second positive voltage application time (step Sa5). HVN1EN is generated based on the added transmission waveform and the first negative voltage application time, and HVN2EN is generated based on the added transmission waveform and the second negative voltage application time (step Sa6).

  A plurality of switching pulses (G1EN, G2EN, HVP1EN, HVP2EN, HVN1EN, HVN2EN) are respectively output to the corresponding switching elements. Switching of the plurality of switching elements is controlled by the plurality of switching pulses (step Sa7). A voltage signal corresponding to the added transmission waveform is generated by the switching control (step Sa8).

According to the configuration described above, the following effects can be obtained.
According to the ultrasonic diagnostic apparatus 1, it is possible to execute control to make a voltage at a zero level over a predetermined time at a boundary portion of voltage transition using a dual three-level pulser circuit having a small circuit scale. As a result, the transient response time of the voltage fall can be reduced in the transition from the positive second high voltage to the positive first high voltage (+ V2 → + V1) in the voltage signal. In addition, the transient response time of the voltage rise can be reduced in the transition from the negative second high voltage to the negative first high voltage (−V2 → −V1) in the voltage signal.

  Thus, according to the ultrasonic diagnostic apparatus 1, it is possible to obtain the same performance as that of the five-level pulser circuit. That is, according to the ultrasonic diagnostic apparatus, the same performance as the five-level pulser circuit, two-way simultaneous transmission, two-focus simultaneous transmission, pseudo-Gaussian transmission, transmission apodization, etc., without increasing the circuit scale and cost. Can be executed. From the above, according to the ultrasonic diagnostic apparatus 1, the image quality performance of the ultrasonic image can be improved.

  In addition, each function according to the embodiment can also be realized by installing a program for executing the processing in a computer such as a workstation and developing the program on a memory. At this time, a program capable of causing the computer to execute the method is stored in a storage medium such as a magnetic disk (floppy (registered trademark) disk, hard disk, etc.), an optical disk (CD-ROM, DVD, etc.), or a semiconductor memory. It can also be distributed.

  Thus, according to the ultrasonic diagnostic apparatus 1, the dual-level pulser circuit is used and the performance equivalent to that of the 5-level pulser circuit is ensured without increasing the circuit scale and cost, and the image quality performance of the ultrasonic image is improved. It is possible to provide an ultrasonic diagnostic apparatus capable of

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Ultrasonic diagnostic apparatus, 10 ... Ultrasonic probe, 11 ... Apparatus main body, 13 ... Monitor, 15 ... Input device, 21 ... Transmission part, 23 ... Reception part, 25 ... B mode process part, 27 ... Doppler process part, DESCRIPTION OF SYMBOLS 29 ... Image generation part, 31 ... Image composition part, 33 ... Internal storage device, 35 ... Interface part, 37 ... Control processor (CPU), 41 ... Rate pulse generation part, 43 ... Transmission delay part, 45 ... Pulser control part, 47 ... vibrator 49 ... pulser 51 ... first memory 53 ... second memory 55 ... first delay unit 57 ... second delay unit 59 ... addition unit 61 ... switching pulse generation unit 71 ... high Voltage generating unit 73 ... Switching unit 711 ... First high voltage generating unit 712 ... Second high voltage generating unit GSW1 ... First ground switch GSW2 ... Second ground switch PSW1 ... First positive side switch H, NSW1 ... first negative switch, PSW2 ... second positive switch, NSW2 ... second positive switch, G1EN ... first ground switching pulse, G2EN ... second ground switching pulse, HVP1EN ... first positive switching pulse , HVN1EN ... first negative switching pulse, HVP2EN ... second positive switching pulse, HVN2EN ... second negative switching pulse, tp1 ... first positive voltage application time, tp2 ... second positive voltage application time, tg1 ... first Predetermined time, tn1 ... first negative voltage application time, tn2 ... second negative voltage application time, tg2 ... second predetermined time

Claims (6)

An ultrasonic probe having a plurality of transducers;
A transmitter that transmits ultrasonic waves to the subject via the vibrator;
A receiving unit that receives an ultrasonic echo from the subject via the vibrator;
An image generator that generates image data based on the output of the receiver,
The transmission unit includes a rate pulse generation unit that generates a rate pulse that determines a transmission cycle of the ultrasonic wave, a transmission delay unit that gives a delay time to the transducer for each transducer, and the delayed rate pulse A pulser that generates a voltage signal for driving each of the vibrators in synchronization, and a pulser controller that controls the pulser to generate the voltage signal;
The pulser generates a first high voltage indicating a potential difference between a first potential and a ground potential, and a second high voltage indicating a potential difference between the second potential having an absolute value higher than the first potential and the ground potential. A high voltage generator, and a plurality of switching elements capable of mutually switching the potential between the first potential, the second potential, and the ground potential,
The pulser control unit controls the plurality of switching elements to switch the potential from the second potential to the first potential via the ground potential;
An ultrasonic diagnostic apparatus characterized by the above. The pulsar control unit
When switching the potential from the second potential to the first potential via the ground potential, turning on a switching element for switching the ground potential for a predetermined time;
The ultrasonic diagnostic apparatus according to claim 1. The pulsar control unit
Generating a plurality of switching pulses for controlling the switching element based on the transmission waveform data output from the transmission delay unit, and outputting the generated switching pulse to the switching element;
The ultrasonic diagnostic apparatus according to claim 1. The pulsar control unit
Based on transmission waveform data output from the transmission delay unit, a time point for switching from the second potential to the first potential is specified, and switching related to switching of the ground potential is performed for a predetermined time from the specified time point. Turning on the element,
The ultrasonic diagnostic apparatus according to claim 1. In the computer built in the ultrasonic diagnostic equipment,
A rate pulse generation function for generating a rate pulse that determines the ultrasonic transmission period;
A transmission delay function for giving a delay time to each transducer in the rate pulse;
A voltage signal generation function for generating a voltage signal for driving each of the vibrators in synchronization with the delayed rate pulse;
A switching control function for controlling a plurality of switching elements to generate the voltage signal;
The switching control function controls the switching element to switch the potential from a second potential whose absolute value is higher than the first potential to the first potential via a ground potential serving as a reference for the first and second potentials. about,
A switching control program characterized by realizing the above. Generating a rate pulse that determines the ultrasound transmission period;
Giving the rate pulse a delay time for each transducer;
Generating a voltage signal for driving each of the vibrators in synchronization with the delayed rate pulse;
Controlling a plurality of switching elements to generate the voltage signal,
The switching element controls the switching element in order to switch the potential from the second potential whose absolute value is higher than the first potential to the first potential via the ground potential serving as a reference for the first and second potentials. To control,
A switching control method characterized by the above.

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